/*
 *  Licensed to the Apache Software Foundation (ASF) under one or more
 *  contributor license agreements.  See the NOTICE file distributed with
 *  this work for additional information regarding copyright ownership.
 *  The ASF licenses this file to You under the Apache License, Version 2.0
 *  (the "License"); you may not use this file except in compliance with
 *  the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 *
 */

package com.zhs.gccs.utils.zip.extra;

/**
 * This is a class that has been made significantly smaller (deleted a bunch of
 * methods) and originally is from the Apache Ant Project
 * (http://ant.apache.org), org.apache.tools.zip package. All license and other
 * documentation is intact.
 * 
 * Simple placeholder for all those extra fields we don't want to deal with.
 * 
 * <p>
 * Assumes local file data and central directory entries are identical - unless
 * told the opposite.
 * </p>
 * 
 */
public class UnrecognizedExtraField implements ZipExtraField {

	/**
	 * The Header-ID.
	 * 
	 * @since 1.1
	 */
	private ZipShort headerId;

	/**
	 * Set the header id.
	 * 
	 * @param headerId
	 *            the header id to use
	 */
	public void setHeaderId(ZipShort headerId) {
		this.headerId = headerId;
	}

	/**
	 * Get the header id.
	 * 
	 * @return the header id
	 */
	public ZipShort getHeaderId() {
		return headerId;
	}

	/**
	 * Extra field data in local file data - without Header-ID or length
	 * specifier.
	 * 
	 * @since 1.1
	 */
	private byte[] localData;

	/**
	 * Set the extra field data in the local file data - without Header-ID or
	 * length specifier.
	 * 
	 * @param data
	 *            the field data to use
	 */
	public void setLocalFileDataData(byte[] data) {
		localData = copy(data);
	}

	/**
	 * Get the length of the local data.
	 * 
	 * @return the length of the local data
	 */
	public ZipShort getLocalFileDataLength() {
		return new ZipShort(localData.length);
	}

	/**
	 * Get the local data.
	 * 
	 * @return the local data
	 */
	public byte[] getLocalFileDataData() {
		return copy(localData);
	}

	/**
	 * Extra field data in central directory - without Header-ID or length
	 * specifier.
	 * 
	 * @since 1.1
	 */
	private byte[] centralData;

	/**
	 * Set the extra field data in central directory.
	 * 
	 * @param data
	 *            the data to use
	 */
	public void setCentralDirectoryData(byte[] data) {
		centralData = copy(data);
	}

	/**
	 * Get the central data length. If there is no central data, get the local
	 * file data length.
	 * 
	 * @return the central data length
	 */
	public ZipShort getCentralDirectoryLength() {
		if (centralData != null) {
			return new ZipShort(centralData.length);
		}
		return getLocalFileDataLength();
	}

	/**
	 * Get the central data.
	 * 
	 * @return the central data if present, else return the local file data
	 */
	public byte[] getCentralDirectoryData() {
		if (centralData != null) {
			return copy(centralData);
		}
		return getLocalFileDataData();
	}

	/**
	 * @param data
	 *            the array of bytes.
	 * @param offset
	 *            the source location in the data array.
	 * @param length
	 *            the number of bytes to use in the data array.
	 * @see ZipExtraField#parseFromLocalFileData(byte[], int, int)
	 */
	public void parseFromLocalFileData(byte[] data, int offset, int length) {
		byte[] tmp = new byte[length];
		System.arraycopy(data, offset, tmp, 0, length);
		setLocalFileDataData(tmp);
	}

	/**
	 * @param data
	 *            the array of bytes.
	 * @param offset
	 *            the source location in the data array.
	 * @param length
	 *            the number of bytes to use in the data array.
	 */
	public void parseFromCentralDirectoryData(byte[] data, int offset, int length) {
		byte[] tmp = new byte[length];
		System.arraycopy(data, offset, tmp, 0, length);
		setCentralDirectoryData(tmp);
		if (localData == null) {
			setLocalFileDataData(tmp);
		}
	}

	/**
	 * Create a copy of the given array - or return null if the argument is
	 * null.
	 */
	private static byte[] copy(byte[] from) {
		if (from != null) {
			byte[] to = new byte[from.length];
			System.arraycopy(from, 0, to, 0, to.length);
			return to;
		}
		return null;
	}
}
